Double all filtration values.

It was using the Cech convention, not the Rips, so the Rips approximation was not close to the Rips, which is likely to confuse users.


git-svn-id: svn+ssh://scm.gforge.inria.fr/svnroot/gudhi/branches/sparserips-glisse@3188 636b058d-ea47-450e-bf9e-a15bfbe3eedb

Former-commit-id: 7b948c956f39dc75931cb00a64516d08ff42e435

1 files changed, 3 insertions, 2 deletions

diff --git a/src/Rips_complex/include/gudhi/Sparse_rips_complex.h b/src/Rips_complex/include/gudhi/Sparse_rips_complex.h
index e1e3a951..b8850d00 100644
--- a/src/Rips_complex/include/gudhi/Sparse_rips_complex.h
+++ b/src/Rips_complex/include/gudhi/Sparse_rips_complex.h
@@ -152,10 +152,11 @@ class Sparse_rips_complex {
             GUDHI_CHECK(lj <= li, "Bad furthest point sorting");
             Filtration_value alpha;
 
+            // The paper has d/2 and d-lj/e to match the Cech, but we use doubles to match the Rips
             if(d * epsilon <= 2 * lj)
-              alpha = d / 2;
+              alpha = d;
             else if(d * epsilon <= li + lj && (epsilon >= 1 || d * epsilon <= lj * (1 + 1 / (1 - epsilon))))
-              alpha = d - lj / epsilon;
+              alpha = (d - lj / epsilon) * 2;
             else continue;
 
             add_edge(pi, pj, alpha, graph_);